The programming language is the language used to give instructions to a machine. For me, it is very similar to a natural language. What do you mean by "programming notation" ?
To put it another way, since the quote mentioned this, I don't think it's fair to compare a dictionary for a natural language to a dictionary for a computer language, because they're quite different things. One records and documents a process already happening [language evolution], while another is the process itself [language creation].
Just a personal opinion, that's all -- I just think analogies can be stretched too far, and by calling computer languages "languages" I think it's backed the discourse about them into a corner a little bit. Which is not to say all comparisons between computer language and "normal" languages are wrong, just that they're not really appropriate in this instance when discussing copypwritability.
In that sense, programming languages, regular expressions, and natural language can all be identified by what types of grammar can define them.